Operating mechanism for lifting-jacks



c. 0. DERBY. OPERATING MECHANISM FOR LIFTING JACKS- APPLICATION FILEDMAR. 12, I920- 1,3?fi868 Patented Mam 2Q, 1921..

CHARLES D. DERBY, 01F D.-.YTO1\T, OHIO, ASSIGNOB TO THE JOYCE-CRIDLANDCQM'PANY, 01-5 DAYTON, OHIO, A CORPORATION OF OHIO.

Specification of Letters 2atent.

or ented 29, 15521.

Application filed March 12, 1920. Serial No. 365,173.

To all whom it 722( concern Be it known that l, Crrannns D. DERBY, acijaen of the United States, residing at too, in the county ofMontgomery and Ohio, have invented certain new :ful improvements inOperating hanIsm for Lifting-lacks, of which the owingz is aspecification, reference being therein to the accompanying drawing. isinvention relates to operating -mecha nism i r lifting jacks and thelike, and more particularly to what is known as a fine toothed ratchetmechanism.

@ne object of the invention is to provide a mechanism or" this kindwhich will be simple in its construction and operation; and in which thepawl will engage the ratchet wheel with a strong gripping action andwill have no tendency to slip.

A further object of the invention is to provide a mechanism of this kindwhich can be easily reversed by the manipulation of the lever andwithout the necessity of the operator crawling under or reaching underthe load.

Other objects of the invention will appear as the mechanism is describedin detail.

Figure l is a perspective view of a jack embodying; my invention; Fig. 2is a transverse sectional view. taken through the ratchet wheel; andFig. 3 is a side elevation of the ratchet mechanism.

In these drawings I have illustrated one embodiment of my invention andhave shown the same as applied to a lifting jack of a well knownconstruction and which is designed in the present case, as a truck I Itwill be understoood, however, that this embodiment of the invention hasbeen chosen for the purpose of illustration only and that the inventionbe applied to jacks or various kinds, or to other devices, in which aratchet mechanism may be employed.

its here illustrated, the jack comprises a base 1 having mounted thereina screw 2 in which is mounted a second screw 3 to the upper end of whichis secured the cap, or load engaging member, 4. The telescoping screws 2and 3 constitute the lifting mem ber of the jack and are threaded inopposite directions so that the rotation of the outer sirew 2 will notonly cause this screw to be moved lengthwise of the base 1 but will alsocause the inner screw 3 to be moved length- ,M o. a no to wiserelatively to the outer screw. Rotatory movement is imparted to theouter screw by means oi. a. suitable actuating member, such as a ratchetwheel 5 which is rigidly secured to the upper end thereof and which inthe present instance is provided with radial teeth which are of all-shape. Rotatably mounted for movement about the axis of the ratchetwheel is a lever supporting structure which, as here shown, comprisestwo plates 6 and 7 arranged respectively above and below the ratchetwheel. are preferably rigidly connected one to the other and in thepresent instance they are united by a semi-circular flange 8 which isformed integral therewith and extends about approximately one half ofthe ratchet wheel. The plates and flange thus constitute a housinginc-losing the ratchet wheel but open along one edge to expose the teethof the ratchet wheel for engagement by the pawl. The plates 6 and 7 areprovided with outwardly extending portions 9 to receive between them theend portion of a lever 10, which preferably comprises a socket portionadapted to receive a bar, or spike, 11. Rigidly secured to the lever andextending; in opposite directions therefrom along the edge of theactuating member are two projections or pawls 12 and 13 each having'near its outer end a portion adapted to he moved into and out ofoperative engagement with the actuating member by the manipulation ofthe lever. When the actuating member is in the form of a ratchet wheelthe pawl may be provided with teeth and, in the present instance, eachpawl is shown a having a series oi t -shaped teeth adapted to mesh withthe teeth of the ratchet v reel. The pawls 12 and 13 are of such lengthand are so arranged with relation to the lever that when the lever ismoved about its axis the pawl on that side toward which the lever ismoved will be moved in a substantially radial direction into engagementwith the teeth of the ratchet wheel, thus causing the teeth of the pawlto be seated firmly in the recesses be tween the teeth of the ratchetwheel and to the same with a gripping action, which will eii ectuallyprevent any slipping or" the pawls relatively to the ratchet wheel. Itwill be apparent that when the lever is actuated it will first moveabout the axis of its pivotal connection to the supporting These platesstructure to cause the pawl on that side thereof toward which it ismoved to engage the teeth of the ratchet wheel and that at ter thisengagement has been established, the continued movement of the leverwill cause the supporting structure and the ratchet wheel to rotate thusactuating the lifting member. Upon the return movement of the lever itwill be first moved about the axis of its pivotal connection to thesupporting structure to disengage the pawl from the ratchet wheel andthe further movement thereof will'rotate the supporting structurerelatively to the ratchet wheel to permit the lever, and the pawl to bereturned to their initial positions, Means provided to so limit thepivotal movement of the lever in a return direction that the pawl on theopposite side thereof will. not be moved into engagement with theratchet wheel but will be held in a neutral position while returnmovement is imparted to the lever and to the supporting structure. Tothis end I have mounted on the supporting structure a stop 14 arrangedin the path oi a dog 15 mounted upon the lever and so arranged that whenthe lever has been moved to sul stantially a central position withrelation to the supporting structure, the dog will engage the stop andcheck the pivotal movement of the lever. The dog is preferably yieldableso that it can be moved across the stop to permit the mechanism to bereversed, to move the lifting member in the opposite direction. In orderthat the lever may assume its central, or neutral, position when thedog'15 is located on either side of the A stop 14 l have pivotallymounted the stop,

as shown at 16, and have provided the same with oppositely extendingprojections 17 and 18 arranged to engage the opposite sides of a fixedstop 19 on the supporting structure, this fixed stop comprising, in thepres ent instance, the head of a bolt 20 by means of which the lever ispivotally connected with the supporting structure. The projections 17and 18 on the movable stop 1st are so arranged with relation to thelined stop 19 that the movable stop will have a limited pivotalmovement, which is suficient to position the same on either side of acentral line, that is, a line extending through the axis of the ratchetwheel and through the axis of the lever. The arrangement, of the movablestop is also such as to permit this stopto move with the lever until thepawl has engaged the ratchet wheel, as shown in Fig. 2. Upon the returnmovement of the lever, from the position shown in full lines in Fig. 2,the stop will move about its axis 16 until the projection 17 engages thefixed stop 19 and thus checks the pivotal movement of the lever andcauses the supporting structure to move therewith. W hen it is desiredto reverse the operation of the ack this may be accomplished by applyingsuflicient force to the lever to cause the pawl 15 to yield and rideover the end of the movable stop 14. This may be quickly and easilyacconplished by a jerk on the end of the lever, thus avoiding anynecessity for the operator crawling under, or reaching under, the load.

The operation of the mechanism will be readily understood from theforegoing d scription and will be apparent that l have prvided anoperating mechanism which is very simple both in its construction entthat the operating mechanism may be very quickly and easily reversedfrom a point remote from the jack.

l hile l have shown and described one embodiment of my invention 1 Wishit to he understood that I do not desire to be limited to the detailsthereof as various modifications may occur to a person skilled in theart.

Having now fully described my invention what I claim as new and desireto secure by Letters Patent is: l

1. in a lifting jack, a lifting member, a ratchet wheel operativelyconnected therewith, a lever supporting structure mounted :lor rotationabout the axis of said ratchet wheel, a lever pivotally; mounted on saidstructure, pawls carried by said lever and extending in oppositedirections therefrom about said ratchet wheel and so arranged that themovement of said lever about its axis will cause that pawl toward whichthe lever is moved to engage said ratchet wheel, and means to limit thereturn movement of said lever about its pivotal connection to saidsupporting structure, said means being reversible by the manipulation o1said lever to enable the movement oi said lever to be limited in eitherdirection.

2. In a lifting jack, a lifting member, a

ratchet wheel operatively connected there- 7 with, a lever supportingstructure mounted and cooperating stops carried by said lever and saidsupporting structure to limit the return movement of said lever aboutits pivotal connection to said supporting structure, one of said stopsbeing yieldable to permit it to pass the other stop and to re verse theoperation of the jack.

3. In a lifting jack, a lifting member, a ratchet wheel operativelyconnected therewith, a lever supporting structure mounted for rotationabout the axis of said. ratchet wheel, a lever pivotally mounted on saidstructure, pawls carried by said lever and extending in oppositedirections therefrom about said ratchet wheel and so arranged that themovement of said lever about its axis will cause that pawl toward whichthe lever is moved to engage said ratchet wheel, a stop mounted on saidsupporting structure for a limited pivotal movement, and a dog yieldablymounted on said lever and arranged to cooperate with said stop to limitthe movement of said lever in one direction about its pivotal connectionwith said supporting structure.

4. In a lifting jack, a lifting member, a ratchet wheel operativelyconnected therewith, a lever supporting structure mounted for rotationabout the axis of said ratchet wheel, a lever pivotally mounted on saidstructure, pawls rigidly secured to said lever and extending in oppositedirections therefrom about said ratchet wheel and so arranged that themovement of said lever about its axis will cause that pawl toward whichthe lever is moved to engage said ratchet wheel, a dog yieldably mountedon said lever, a stop pivotally mounted on said support ing structureand having a part arranged to cooperate with said dog to limit themovement of said lever in one direction about its pivotal connectionwith said supporting structure, said movable stop having oppositelyextending projections, and a fixed stop carried by said supportingstructure and arranged between the projections of said movable stop tolimit the pivotal move ment of the latter.

In a lifting jack, a lifting member, a ratchet wheel operativelyconnected therewith, a lever supporting structure mounted for rotationabout the axis of said ratchet wheel, a lever pivotally mounted on saidstructure, pawls rigidly secured to said lever and extending in oppositedirections there from about said ratchet wheel and so arranged that themovement of said lever about its axis will cause that pawl toward whichthe lever is moved to engage said ratchet wheel, and cooperating stopscarried respectively by said lever and said supporting structure tolimit the movement of said lever in one direction about its pivotalconnection with said supporting structure, one of said stops being ofsuch a character that the rela- ,scs.

tive positions of the two stops can be reversed by the manipulation ofsaid lever.

6. In a lifting jack, a lifting member, a ratchet wheel operativelyconnected therewith, a lever supporting structure mounted for rotationabout the axis of said ratchet wheel and comprising upper and lowermembers, a lever having a part extending between the upper and lowermembers of said supporting structure and pivotally connected therewith,said lever also having pawls formed integral therewith and extending inopposite directions therefrom about said ratchet wheel, a dog yieldablymounted on said lever, and a stop mounted on said structure to cooperatewith said dog and having a limited pivotal movement to permit it to bepositioned on either side of said dog when said lever is in a neutralposition.

7. In a lifting jack, a lifting member, an actuating member operativelyconnected with said lifting member, a lever supporting structure mountedfor rotation about the axis of said actuating member, a lever pivotallymounted on said structure, and pawls rigidly secured to said lever andextending laterally therefrom in different directions, each pawl havinga portion arranged to be moved into and out of gripping engagement withsaid actuating member by the move ment of said lever about its axis, andmeans to limit the return movement of said lever, said means beingreversible by the manipulation of said lever.

8. In a lifting jack, a lifting member, an actuating member operativelyconnected with said lifting member, a lever supporting structure mountedfor rotation about the axis of said actuating member, a lever pivotallymounted on said structure, pawls secured to said lever and extendinglaterally therefrom in difierent directions, each pawl having a portionarranged to be moved into and out of gripping engagement with saidactuating member by the movement of said lever about its axis, andcooperating stops to limit the return movement of said lever about itspivotal connection to said supporting structure, one of said stops beingreversible to engage either side of the other stop and said other stopbeing adjustable relatively to the reversible stop.

9. In a lifting jack, a lifting member, an actuating member operativelyconnected with said lifting member, a lever supporting structure mountedfor rotation about the axis of said actuating member, a lever pivotallymounted on said structure, pawls secured to said lever and extendinglaterally therefrom in different directions, each pawl having a portionarranged to be moved into and out of gripping engagement with saidactuating member by the movement of said lever about its axis, a stoppivotally mounted on said lever supporting structure, means to limitsaid lifting member, a lever supporting structure mounted for rotationabout the axis of said actuating member, a lever pivetally mounted onsaid structure, pawls secured to said lever and extending laterallytherefrom in different directions, each pawl having a portion arrangedto be moved into and out of gripping engagement with said actuatingmember by the movement of said lever about its axis, a stop mounted onsaid lever supporting structure, a second stop pivotally mounted on saidlever supporting structure and having parts arranged on the oppositesides of the first mentioned stop to limit the movement of said pivotedstop, and a yieldable stop carried by said lever and adapted to engageeither side of said pivoted stop.

11. In a lifting jack, alifting member, an actuating member operativelyconnected With said lifting member, "a lever "supporting structuremounted for rotation about the axis of said actuating member, a leverpivotally mounted on said structure, and paWls rigidly secured to saidlever and extending laterally therefrom in different directions, eachpawl having a portion arranged to be moved into and out of grippingengagement with said actuating member by the movement of said leverabout itsaxis, and cooperating stops carried by said lever and saidsupporting structure, respectively, to limit the return movement of saidlever about its pivotal'connection to said supporting structure, one ofsaid stops being yieldable to permit it to pass the other stop and toreverse the operation of the V In testimony whereof, I atlix myslgnature hereto.

CHARLES l). DERBY.

